Films, fabrics, and fibrous substrates including textiles have been treated with fluorochemical uncrosslinked urethanes to impart water and soil repellency.
Microporous films prepared by thermally-induced phase separation (TIPS) methods are known. U.S. Pat. Nos. 4,539,256 (Shipman), 4,726,989 and 5,120,594 (Mrozinski) and 5,260,360 (Mrozinski et al.) describe such films containing a multiplicity of spaced, randomly dispersed, equiaxed, nonuniform shaped particles of a thermoplastic polymer, optionally coated with a liquid that is immiscible with the polymer at the crystallization temperature of the polymer. Micropores allow permeability to gases, including moisture vapor, but can be impermeable to high surface tension liquids such as water.
Microporous membranes have been coated with a urethane such that the pores are filled and the membrane is impervious to passage of gases. On the other hand, U.S. Pat. No. 5,286,279 describes a gas permeable membrane coated with a fluorochemical urethane wherein the urethane is prepared from either 1,4-cyclohexane diisocyanate or methane 4,4'-diphenyl diisocyanate.